Field of the Invention
A consensus exists today by transportation and highway designers and planners that there is an increasingly critical need to return much of what has become highway cargo to rail, with immediate action needed now in the East and shortly throughout the nation. Highway traffic volume continues to increase alarmingly while highway capacity is not expected to expand correspondingly, giving but an indication tody of what the problem will become if the back-to-rail trend is not expedited. At this time that change consists mostly of piggy-back cargo in longhaul (transcontinental, 3rd or 4th day service). The critical next step is to move to rail the much larger volume of radial overnight and 2nd day traffic from the 25 or 30 major national distribution centers. As was realized 40-50 years ago that type of cargo cannot be integrated into conventional rail operations. That attempt brought about today's broad highway transport problem.
The requirements for moving cargo back to rail include a separate rail operating entity perhaps not unlike AMTRAC, though not as a government agency, using present rails under contract with the owners, utilizing available light power units pulling trialers of the type here as one option. Semi-trailers of the type here are not now available onr is a coupler of this type and capacity available to move combinations in excess of, e.g., 200 trailer each grossing 55,000 lbs--or exceeding 11 million pounds dead weight not including the required effort to overcome friction, trackage deflection and varying elevations. Those are the problems and conditions addressed by the trailer and the coupler of this invention.